Vacuum copyholder



March 12, 1929.

F. DOUTHITT VACUUM COPYHOLDER Filed Nov. 24, 1924 ,I LL,

'impressions in various kinds of work.

Patented Mar. 12, 1929.

FLETCHER DCUTHITT, on DETROIT,` MICHIGAN.

' VACUUM CoPYHonnEit.

Application iled Novemberizll, 1924. vSerial No. 751,823.

This invention relates to holding means` for flat material'and articles and my invention aims to utilize vacuum or a reduction inl atmospheric pressure'for evenly and positively holdingilat `material or articles on a surface, so that there willr be no danger of accidental displacement, no gap between vthe material and the sur-face on which it isheld, and no wrinkled or ybuckled portion-ot the material which might cause As an instance of holding fiat material in various arts, there is that `or" holding celluloid iilins in a perfect plane in a camera while making a photograph; holding celluloid tints, of the Ben Day process, while transferring ink to `metal plates, holding Celluloid upon which half tone' or grained tints have been printed in vperfect contact with drawings while lart work is performed or' while photographing to avoid shadows,

and for eliminating the curve of any photographie negative to insure aV perfect plane while photographing. Otheruses are that of holding. copies without a cover glass; holding paper on a drawing board without thumb tacks, and holding copper or other metallic plates on a router bed while being'y routed.

My invention further aims to use a finely lined supporting surface for flat material material being placed on the support air niay be withdrawn from the chamber to produce a suction which will hold the material on the support.

My invention will bey hereinafter specifically described and then claimed, and reference will now be had to theV drawing wherein Figure l is a plan of a holding device partly-broken away and partly in plan;

a traine 6.

Fig. 2 is an end view of the device partly broken away and partly in section, and

liig.` 3 is an enlarged detail sectional view of a portion of a support; y

In the drawing, the reference numeral l denotes a flat support-and on lthe upper tace et said support is a holding area having for its boundary channels or grooves 2 communicating with a plurality of apertures extending from the upper face of the support to the lower face thereof. The holding area of vthe support l is lined or grooved to provide very line channels l having the ends thereofy communicating with the channels 2.

in Fig. 3, and in actual practice are just as small and close together as it is possible to makethe same, whereby the approximately holding area sothat its edges will overlap or.

extend beyond the channel 2, and to facilitate temporarily holding a sheet of paper 5 in place, I may provide the support l with rllhe frame 6 may be hingedly The y `'lhe channels have been greatly exaggerated 'A supliorted as at from one of two feet or cleats 8 Yattached to the lower face of the maybe spring lsupport l, and said frame closed vso that it will not accidentally open while the device is being handled.

The feet or cleats 8 may extend along the end edges of the support andare mainlv employed to hold the relative to a table top clearance Jfor a channel attached to 'the lower in order to provide vacuum. chamber 9 tace of the support l and communicating with the apertures 3. The vacuum chamber 9 1s sealed relative .to

thelower race of the support l and said chamber has a connection 10 whereby a pump may beused for; exhausting air from the vacuum chamber.

In some instances the vacuum chamber 9 may serve as supporting means for the support l, then again, the legs or cleats 8 may be dispensed with when thefsupport l is built into a table top,` camera, machine or other structure.

The frame 6 may be of greater areathan the support l to facilitate opening said frame or it may be provided withl a knob 1l for such purposes. In some instance the support l elevated i frame may be entirely discarded but it is preferable touse' the same Where iilms, large sheets of paper, celluloid or tracing linens Which contain roll or curl are to be temy porarily held.

stance a printing press, it may be necessary V to remove the sheet of paper or other material by air pressure forced into the chamber 9, apertures 3, and channels 2 anda to l overcome any Istatic elasticity that may tend to' hold the sheet or' paper or material on the support. Such expelling of the sheet of paper may be necessary in a printing press where sheets are to be expeditiously handled in Which case the connection l0 may be provided With a two-Way valve control.- ling the supply of air to the vacuunicha-mber for expelling purposes and the Wit-hdravval of air from the vacuum chamber for 4holding purposes.

I attach considerable importance tothe channeled support l which has its channels very closely assembled and extend-ing from., one of the channels 2 to another preferably with the channels l diagonally disposed' as indicated in Fig. l. VlVith such'ine chan nels it will be possible to .Withdraw air from practically the entire lower face of the sheet of paper and there Will be no opportunity for the lpaper to buckle or lie uneven on the surface of the support. This is adtacks, clamps or like devices.

One embodiment of my invention hasV been illustrated, but it is to be understood that'the structuralV elements are susceptible to. such. variations and modifications as Jall Within 'the scope of the appended claims.

lllhatl claim iszl. Holding means for material comprising av sup-port having a Vacuum chamber from which air may be Withdrawn, saidsupport having alarge supporting area .bounded by channels andy apertures communicating` With said vacuum chamber,l said supw port having a surface formed ci fine closely assembled. parallel grooves with4 the ends of said grooves communicating with the boundary channels and apertures, said support surface adapted to be covered by the material to be held on said supper 2. A sheet holding device comprising a support having a finely grooved supporting area, channels connecting' the fine grooves of said support, and a connection in com- Inunicationy with the-channels o said sup port so that air may be Withdrawn from the grooves of Vsaid support When said grooves are covered by a sheet.

In testimony whereof I ailix my signature.

FLETCHER DQUTHITT. 

